#include <bits/stdc++.h>
using namespace std;

#define int int64_t
#define endl "\n"

using PII = pair<int, int>;
using TII = tuple<int, int, int>;
template<class T>
using V = vector<T>;
using i64 = long long;
using i128 = __int128;
using u64 = unsigned long long;

#define FOR(i, a, b) for (int i = (int)(a); i <= (int)(b); i++)
#define FOR2(i, a, b, c) for (int i = (int)(a); i <= (int)(b); i += c)
#define FORD(i, b, a) for (int i = (int)(a); i >= (int)(b); i--)
#define FORD2(i, b, a, c) for (int i = (int)(a); i >= (int)(b); i -= c)
#define ALL(a) a.begin(), a.end()
#define RALL(a) a.rbegin(), a.rend()
#define lowbit(x) ((x)&(-x))
#define RE return;
#define Yes cout << "Yes" << endl;
#define YES cout << "YES" << endl;
#define No cout << "No" << endl;
#define NO cout << "NO" << endl;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define sz size()

void solve() {
    int n, q, k;
    cin >> n >> q >> k;

    V<int>w(n + 1), pre(n + 2, 0);

    FOR(i, 1, n)cin >> w[i];

    FOR(i, 2, n - 1){
        pre[i] = pre[i - 1] + (w[i + 1] - w[i - 1] - 2);
    }

    while (q--){
        int l, r;
        cin >> l >> r;
        if (l == r){
            cout << k - 1 << endl;
        } else{
            int ans = pre[r - 1] - pre[l];
            ans += w[r] - w[r - 1] - 1;
            ans += w[l + 1] - w[l] - 1;
            ans += w[l] - 1;
            ans += k - w[r];
            cout << ans << endl;
        }
    }
}

signed main() {
    int Task = 1;

    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    while (Task--) {
        solve();
    }

    return 0;
}